The present invention relates to lubricating compositions containing dispersants.
Modern crankcase lubricants function to prevent carbonaceous and sludge deposits. Within these crankcases, detergents and dispersants are typically employed to keep pistons and other parts free and cleat of deposits. There are several industry standard tests used to evaluate a lubricant's ability to handle deposits and sludge including the Sequence VG, Sequence IIIG, TDi, Cat 1N, OM501 LA and others.
U.S. Pat. No. 4,171,959 discloses a motor fuel composition containing quaternary ammonium salts of a succinimide. The quaternary ammonium salt has a counterion of a halide, a sulphonate or a carboxylate.
U.S. Pat. No. 4,338,206 and U.S. Pat. No. 4,326,973 discloses fuel compositions containing a quaternary ammonium salt of a succinimide, wherein the ammonium ion is heterocyclic aromatic (pyridinium ion).
U.S. Pat. No. 5,254,138 discloses a fuel composition containing a reaction product of a polyalkyl succinic anhydride with a polyamino hydroxyalkyl quaternary ammonium salt.
U.S. Pat. No. 4,056,531 discloses a lubricating oil or fuel containing a quaternary ammonium salt of a hydrocarbon with a Mw of 350 to 3000 bonded to triethylenediamine. The quaternary ammonium salt counterion is selected from halides, phosphates, alkylphosphates, dialkylphosphates, borates, alkylborates, nitrites, nitrates, carbonates, bicarbonates, alkanoates, and O,O-dialkyldithiophosphates.
U.S. Pat. No. 4,248,719 discloses a fuel or lubricating oil containing a quaternary ammonium salt of a succinimide with a monocarboxylic acid ester.
U.S. Pat. No. 4,253,980 and U.S. Pat. No. 4,306,070 disclose a fuel composition containing a quaternary ammonium salt of an ester-lactone.
U.S. Pat. No. 3,778,371 discloses a lubricating oil or fuel containing a quaternary ammonium salt of a hydrocarbon with a Mw of 350 to 3000 and the remaining groups to the quaternary nitrogen are selected from the group of C1 to C20 alkyl, C2 to C8 hydroxyalkyl, C2 to C20 alkenyl or cyclic groups.
U.S. Pat. Nos. 7,951,211 and 7,947,093 disclose quaternary ammonium salt detergents for use in fuel compositions to reduce intake valve deposits.
Recent industry engine oil upgrades place increasing demands on the lubricant with regards to deposit performance. For instance, the new ILSAC GF-5 specification requires a 4.0 piston merit rating in the Sequence IIIG (vs. 3.5 for GF-4). Increased deposit requirements call for new chemistry and formulation strategies.